This invention relates to a cutting tool which comprises a tool holder, a cutting insert seat and a cutting insert secured in the seat by means of a clamping mechanism. The cutting insert seat and the cutting insert are replaceable either as a unit or separately from one another.
In known cutting tools the cutting inserts are secured to a tool holder body. Thus, according to Swiss Pat. No. 622,200, for securing the cutting insert, a clamping body is provided which has a clamping claw and a hollow cylindrical guide member. The clamping body is arranged with a radial play in the tool holder body and further, the clamping body has, at its side oriented away from the clamping part of the clamping claw, an abutment face which is essentially parallel to the axis of a securing screw and perpendicular to the longitudinal axis of the tool holder body. Such a holding arrangement which permits the accommodation of reversible cutting inserts of only one particular size is particularly disadvantageous because of its enlarged (widening) configuration.
It has been further proposed to anchor the cutting insert together with a replaceable support element which corresponds to the size of the cutting insert, in the tool holder by means of a securing bolt which passes medially through the cutting insert and the support element. In such an arrangement too, the projecting edge of the head of the securing screw has impeded several operative processes or processes directed to the replacement of cutting inserts. Further, to perform a cutting insert replacement, the securing bolt has to be entirely screwed out of the tool holder and screwed back after replacement of the cutting insert
Further, in German Offenlegungsschrift (Application Published Without Examination) No. 2,746,958 there are disclosed support elements for a reversible cutting insert which comprise a cylindrical part insertable in a radial direction in the tool body and forming an axial support for the reversible cutting insert as well as an arm which is a one-piece component with the cylindrical part and which extends therefrom essentially perpendicularly and forms a radial support for the cutting insert. Such a support element is also present in cutting tools of the earlier-described type and serves as a clamping element. Such an arrangement, however, requires narrow manufacturing tolerances between the tool shank and the support member in order to prevent the still frequent deformation of the reversible cutting insert in the insert seat. The cause of such a disadvantageous occurrence resides in the fact that because of the required central positioning of the clamping element with respect to the insert seat provided in the support piece and the oblique engagement face in the longitudinal direction, the geometry of the arrangement is overdefined. For operating the clamping element, a hexagonal sleeve wrench is needed which has to be introduced into a cylindrical opening provided for this purpose, which, because of its inconvenient location, is often soiled during service by scale dust and chip fragments.